Using Geographic Information to Acquire Wild Crop Germplasm for Ex Situ Collections: II. Post-Collection Analysis

Without committing significant resources in the decision-making process, curators are challenged to identify among newly collected germplasm, exceptional accessions that merit inclusion in ex situ collections. The objectives of this paper were to illustrate how geographic information can be used to infer (i) site uniqueness relative to other sites sampled, (ii) the likelihood that an accession reflects adaptation to the site, and (iii) uniqueness of a given accession relative to other accessions of the same taxon collected. Forage legume germplasm was collected from the western Caucasus Mountains in southern Russia in 1995. Prior to the trip, a database was developed from geographic information system software that included data from Russian maps, orbital satellite imagery, remotely sensed elevation data, and long-term climate data from weather stations. Data were collected characterizing the collection sites. A map was developed that partitioned the collection area into standard landscape units from the GIS-derived climate data. The cross-classification map was used to assess collection coverage and identify sites that had similar ecogeographic characteristics. Germplasm was collected from 41% of the possible moisture and temperature zone combinations. Site redundancy was also identified. Local passport data, GIS-derived data and the cross-classification map were used to identify accessions of Trifolium pratense L. adapted to acid soil by inferring the influence of micro evolutionary forces such as selection and gene flow that could lead to geographic differentiation. Of 36 accessions, six met the test of being collected from undisturbed sites with acidic soils, being the sole representatives of unique climate classes and having been isolated from other T. pratense accessions. The post-collection analysis provided a cost-effective way of determining the accessions that warranted inclusion into the NPGS T. pratense germplasm collection.
Curators are responsible for developing ex situ germplasm collections that serve the dual purpose of providing useful breeding material in the present and conserving crop gene pools for the future [...]